You aver no record currently exists of British Nuclear Test survivors at any given date save those recorded as being in receipt of a War Pension directly related to nuclear contamination. Other participating countries have compensated all their veterans. They presumably had no difficulty identifying and locating them.
Has MOD been in contact with those countries seeking help on this or analogous matters?

Health physics records were made available to the NRPB/HPA researchers. These provided lists of individuals who had been issued with film badges to record their possible exposure to external radiation and details of any doses above the threshold of detection which had been incurred.

The published reports provide more detail about what is known of the monitoring regime at the tests but the researchers were content that the data available to them was sufficient and they were also happy that their study design was such that significant unreported exposures would also have been apparent to them."

The Ministry of Defence know the figures, or have the ability to obtain them. It was only the results of Film Badges showing a minimal amount of radiation that were kept for the records. Any Film badges showing a high level of radiation was automatically hidden from view and not recorded. The Proof of this: for Operation Pennant 86% of the radiation film badges issued to the TSFG (Technical Forward Services Group) were recorded as missing and 54% went missing for Burgee. It will be interesting to see if the MOD try to deny these statistics! No enquiry was ever held to discover the reasons why these film badges went missing! The Ministry of Defence are deliberately withholding information relating to this period.